How to write scientific names correctly

Writing the scientific names of species (sometimes also called Latin names), is not that complicated.  Just follow these simple rules.

1.  Scientific species names are always italicized. Like this: Quercus rubra. (You do not need to italicize family names.)
2. The genus name is always capitalized. Like this: Taraxacum, Rosa, or Quercus.
3. The species epithet, the part that comes after the genus name and that is specific to this species is always in lower-case letters.  In the past, it was OK to capitalize this as well when it was based on a geographic name or a person's name (example: America, Smith), but no longer.  Examples: americana, smithii, or novae-anglicae. Do not change the ending of the words, the endings are important and there is only one correct ending.
4. Where can you look up correct spellings of species names?  Well, there are probably half a million published scientific names of plants, maybe more, and there is no global list of all correct and accepted scientific species names.  But there are a couple of good resources to check spellings of names:
   
   • IPNI, International Plant Names Index: very taxonomic, highly accurate, does not say which names that are currently used, every published plant species is listed
   • The Plant List: very good and accurate for some families, still in the works for others, tries to indicate if species names are accepted or if they are synonyms of other species
   • USDA -Plants Database (USA only): Good for North American wild and naturalized plants, a few names are outdated, otherwise great, with additional information (maps, synonyms, endangered species, etc.)
   • USDA - National Plant Germplasm System (GRIN): Database of economic plants and their names, worldwide, very good, but not complete. 
   • Wikipedia: In the last couple of years, Wikipedia has become more and more of a reliable source of taxonomic information.  Not all species are included, but there is often correct species (and family) information available there, as well as the correct spelling of Latin names of common plants.